Neurobiology of Sleep - Circadian Rhythms, Sleep-Wake Cycle and Insomnia

There are two major processes that govern the sleep-wake cycle.

1.Circadian process:

The circadian process is linked to an internal clock located in the suprachiasmatic nuclei and synchronised to the time of day by external clues, mainly the light-dark cycle. Melatonin and adenosine regulate the sleep-wake cycle.
All cells in the body contain this core-clock.
Melatonin is a hormone produced by the pineal gland, and its secretion is suppressed by light. Its secretion starts at twilight and peaks during the middle of the night. This is associated with the circadian rhythm.
2. The homeostatic process:
The need for sleep is a function of the time since the last adequate sleep.

There are two systems of sleep-inducing and wake-inducing brain pathways that constitute a flip-flop switch that is responsible for the transition between sleep and wakefulness.
Full article: https://psychscenehub.com/psychinsights/insomnia-assessment-management/

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